The primary goal of the proposed research is to contribute to the understanding of transduction, coding, and processing of sensory information in the peripheral auditory system. Concurrent experimental and theoretical studies of spike discharge patterns and properties of single cochlear nerve fibers and cochlear nucleus neurons are of specific interest. The cochlear nerve studies will emphasize relations to mechanical motion and transduction, with emphasis on linear and nonlinear system analysis. The results of these studies will form the bases for investigation of information processing in the cochlear nucleus. In addition, a Markov process neuron model previously used to account for spontaneous discharge patterns of cochlear nucelus neurons and tone burst responses of certain categories of cochlear nucleus neurons will augment the experimental program. Maximum possible advantage will be taken in both the experimental and theoretical phases of the program of opportunities for the application of advanced engineering concepts and technology. Digital stimulus generation, on-line Fast Fourier analysis of data, fully automated stimulus control, and advanced acoustic techniques will be used in the experiments. Low noise, low distortion stimulus generation will concurrently be developed. Simulation of models will make use of existing digital and analog computers, as well as specialized macromodular systems designed specifically for this research. Particular emphasis will be paid to that portion of the auditory spectrum below about four kilo-Hertz. Previously developed experimental and data processing techniques are most applicable, and are in turn consistent with exploring the relation between physiologic results and those of speech and psychoacoustics. The degree to which linear and non-linear activities of the peripheral system are functionally important in hearing will continually be questioned.